That thing about fixing a shape one is trying to achieve with their instrument, that problem where you keep repeating the mistake instead of reaching the desired goal of executing the desired fingering or desired stick handling, whatever it is. Just like people trying to lose weight, quit smoking, exercise more, be friendlier whatever it is. Experiencing the error instead of practising the desirable outcome, same loop. You know, if you ever achieved it, it came about from slowing down, from isolating each movement, interrupting whatever is on autopilot. Same mind game.